• Underwater flowering plants provide shelter and other benefits for fish.Kei Uesugi/Lifesize/Getty Images
  
  Underwater flowering plants spend the entire lifecycle beneath the surface of oceans, lakes, ponds and other bodies of water. These plants provide shelter, food and other benefits for a variety of marine life such as small fish, seahorses and crustaceans. These plants are often essential to marine ecosystems and help maintain the delicate balance of life underwater.
  
  

Anubia

• Native to rivers, ponds and other freshwater bodies in western Africa, anubia is an underwater flowering plant commonly used in aquariums. Anubia is extremely hardy and often referred to as "the plastic plant that grows," according to Plant Finder. Anubia grows by attaching its creeping rhizome to logs and rocks from which its sturdy green leaves grow for several years. Anubia produces spiky white flowers under the right conditions. High phosphate levels in the water encourage flowering.
  
  

Aponogeton

• Distributed throughout tropical regions of western Africa, Australia and Asia, aponogetons are widely sold as ornamental plants for artificial ponds and aquariums around the world. There are dozens of different aponogeton species that produce small flower stocks or clusters in a range of colors including yellow, white, pink and pale blue, according to TheKrib.com. Most fish will not eat this plant and it is impervious to apple snails. This bulb plant requires little special care other than occasional fertilizer and adequate lighting.
  
  

Posidonia Oceanica

• Native to the Mediterranean Sea, posidonia oceanica, also known as Neptune grass, is a flowering plant that lives underwater. This common plant forms vast underwater meadows that provide shelter for a range of sea life including sea turtles and small tropical fish. Posidonia oceanica produces small green flowers and fruits commonly known as "olive of the sea," according to the University of British Columbia Botanical Gardens. Movement in the water enables this plant to spread its seeds over the ocean floor. This plant is under threat due to pollution and habitat destruction.
  
  

Zosteraceae

• Zosteraceae refers to another family of flowering seagrass that lives underwater in many temperate and subtropical zones. This perennial herb produces unisexual flowers embedded in a spadix, a protruding spike surrounded by a leafy enclosure in the center of the flower. Like many underwater plants, zosteraceae attach creeping rhizomes to all sorts of underwater objects like rocks and driftwood.